Radios usually have a PTT (Push-to-Talk) key for initiating a call, and a volume control knob for adjusting the volume level. As for the conventional products, a PTT key 201 and a volume control knob 202 are independent components in the radios, as shown in FIG. 1, wherein the PTT key 201 is located at the left side of the radio, and the volume control knob 202 is located at the top of the radio.
Practically both the PTT key and the volume control knob are frequently used, but they are inconvenient for one-hand operation because they are independent with each other. In addition, two openings on the housing of the radio are required for installing both the PPT key and the volume control knob. This design shall affect structural reliability of the radio.